Consonant Changes
In the (pre-)history of Old Icelandic, consonants and consonant clusters underwent various phonological changes as well. Among them it is necessary to mention assimilation, dissimilation (rare), degemination, and devoicing in word-final position (for the last item, see also section 4. below). All these changes eventually contributed to the irregularity of the OIcel. inflectional system as well. Although these phonological changes (naturally) affected all the word-classes, the resulting irregularity of paradigms is most clearly reflected in the verbal system.
For the illustration of irregularity caused by assimilation, it is possible to adduce the regular verb ríkja ‘rule’ compared to the synchronically irregular verb sǿk-ja ‘seek’. The present stem of these verbs is rík- resp. sǿk- but in the preterite the situation becomes different. While the stem of ríkja is the expected rík-t- (older rík-þ-), the preterite stem of sǿkja becomes sótt- due to an early assimilation, cf. sótt- -- *sōht- (-- *sōk-þ-).
Just as was said in the discussion of umlaut and breaking, also assimilation is certain instances does not happen, cf. OIc. þekkja ‘know’ -- *þankjan vs. þenkja ‘think’. Although the latter word-form ultimately reflects *þankjan as well, there is no assimilation of n to the following k in þenkja. This absence of assimilation is explained by the fact that þenkja is a fairly late borrowing from West Germanic, cf. Old Saxon thenkian or Old English þencan ‘think’ (-- *þankjan). In a slightly different case, viz., in the preterite stem rík-t- of the verb ríkja mentioned above there is no assimilation to -tt- (like in sótt-). The different development of seemingly similar verbs is due to the differences in the original shape of the preterite stems of these verbs, cf. *rīk-iđ- vs. *sōk-đ-. In the latter, the consonants k and đ assimilated to -kþ- and later by means of qualitative metathesis to -ht-, and subsequently assimilated to -tt- at a rather early stage. On the contrary, in the stem rīk-iđ- the short vowel -i- hindered a comparable assimilation. Eventually the vowel -i- dropped also in this verb, yielding rīk-đ- (more precisely, rīk-þ-), and, furthermore, probably already in Old Icelandic the new cluster -kþ- underwent the same qualitative metathesis /kþ/ -- /χt/, but the spelling -kt- was preserved for etymological, as well as certain morphonological reasons.
Dissimilation
Dissimilation is fairly rare in Icelandic, yet it has contributed to the development of several irregular paradigms, cf. below:
| maðr ‘man’ (sg.) | teðr/tennr ‘teeth’ (pl.) |
| teðr/tennr: teðr -- *tenn-r, whereas the by-form tennr is analogical |
|
| Accmann | teðr/tennr |
| to˛nnum | |
| Gen.man(n)s | tanna |
Degemination
Degemination occurs commonly in consonant clusters of the type -C1C1C2(C3)-, cf. søkkva ‘sink’ (transitive v.) vs. søkþa ‘id.’ (1. p. sg. preterite), or spenna ‘to make tense’ vs. spenta ‘id.’ (1. p. sg. pret.), etc. In numerous instances geminates are restored contrary to what seems to be a phonological reduction rule, cf. søkkta, spennta, etc. The reason for the restoration of geminates is primarily analogy, to be discussed in 2. below. In certain instances of a different type, cf. leggja ‘lay’ (inf.) or ‘legs’ (gen. pl.), bekkja ‘benches’ (gen. pl.), etc., the spelling would seem to be calling for degemination. However, it does not happen, because the consonant j in such verbs only denotes the frontness of the preceding stop /g´:/, and does not represent an individual phoneme /j/.
Devoicing in word final position
Devoicing in word-final position has led to certain irregularities as well. The consonants that were affected more frequently than others were d, g and γ ‹g›. The consonant γ in absolute final position would become /h/ and disappear, engendering irregular development of the preceding mono- and diphthongs, cf. the development of the 1./3. p. sg. preterite of the verb stíga ‘step’ (-- *stīγan): Proto-Scandinavian *staiγ -- *staih -- *stē -- OIc. sté. Otherwise, the diphthong *ai usually developed into OIc. ei, cf. *baiđ ‘waited’ -- OIc. beið, *skain ‘shined’ -- OIc. skein, etc. It also developed into ei in those word-forms, where γ was not final, e.g. 2. p. sg. steig-t -- *staiγ-t. However, due to system pressure (“Systemzwang”) a new phonologically irregular by-form steig was formed both for the 1. and the 3. persons.
The disappearance of the word-final /h/ (originally, γ) in a similar way affected the diphthong au, irregularly changing it to ō (OIc. ó), cf. OIc. fló ‘flew’ -- *flauh -- *flauγ instead of the expected au, cf. OIc. skaut ‘shot’ -- *skaut, etc. In a similar fashion, the monophthong a was lengthened to ā, cf. vá ‘hit (with a weapon)’ -- *wah -- *waγ.
As a result of devoicing in word-final position, the consonant /d/ often devoiced and subsequently assimilated preceding sonorants, cf. OIc. batt ‘bound’ (1./3. p. sg. pret.) -- *bant -- *bant -- *band, etc. The consonant /g/ often behaved in the same way, devoicing and assimilating a preceding nasal, cf. sprakk ‘exploded’ (1./3. p. sg. pret.) -- *sprank -- *sprank -- *sprang. Since in those word-forms where the conditions for word-final devoicing were not met, devoicing did not occur, paradigms eventually became quite irregular, cf. singular sprakk vs. plural sprungum, or singular batt vs. plural bundum.
Just like in all previous discussions, also here it has to be noted that for various reasons neither devoicing nor assimilation occurred in a number of instances in which the consonants /g/ and /d/ became word-final at the Old Icelandic stage, cf. so˛ng ‘sang’ (1./3. p. sg. pret.; orig. -- *sangw), not *so˛kk or *so˛nk, or bind ‘bind’ (1. p. sg. present; orig. -- *bindu), not *bitt or *bint.
Verner's Law
By the phonological change, established by the above mentioned law, certain voiceless consonants of the Germanic proto-language became voiced, depending on the position and the motion of primary word-stress. The subsequent development of the new consonant pairs sometimes was extremely divergent, cf. Germanic *káus ‘chose’ (1./3. p. sg. pret.) vs. kus-úm ‘id.’ (1. p. pl. pret.) in Scandinavian yielded *káus (-- OIc. kaus) resp. *kúz-um, the latter eventually developing into *kúr-um (-- OIc. kurum). Thus, two alomorphs arose: one kaus-, and the other kur-. In other instances one of the consonants could assimilate with neighbouring consonants, cf. Germanic *fánþ ‘found’ vs. *funþúm -- Scand. *fánþ resp. *fúnđum -- OIc. fann resp. fundum, or could altogether disappear, cf. Germanic *fálh ‘hid’ vs. fulh-ín-az (past ptc.) eventually became OIc. fal-Ø vs. fólginn.
Verner’s law is much better reflected in the verb system, and has produced a numerous irregular forms, as well as caused paradigmatic split in a number of instances.